In part three of our series on neurostimulation treatments for ‪‎mental illness‬, we look at repetitive transcranial magnetic stimulation (rTMS), a form of treatment that first came into use in the 1980s and was approved by Health Canada in 2002 for treatment-resistant depression.

At Toronto Western Hospital, part of the University Health Network, rTMS is offered to patients suffering from refractory ‪depression‬, and is also being studied for its use in postpartum depression, ‪OCD‬, ‪bulimia‬, and is soon to be investigated for its use in the treatment of borderline personality disorder.

Though it requires more of a time commitment than other treatments, rTMS is thought to be less invasive than DBS and ECT, and more tolerable than many treatments including traditional medications, as often the only side effect patients report is some scalp discomfort/headache during the procedure."Unlike medications or therapy, rTMS treats these disorders by stimulating the brain’s neurons directly. It does this using pulsed magnetic fields that are as strong as the one in an MRI scanner, but focused into an area the size of a toonie. The pulses are applied non-invasively through a magnetic coil held against the scalp. By applying repeated pulses of magnetic stimulation over time, rTMS can gradually increase or decrease the activity in the region of the brain underneath the magnetic coil. In major depression, and many other kinds of psychiatric and neurological illnesses, there are parts of the brain that are abnormally underactive or overactive. Over a series of treatment sessions, rTMS can correct these abnormalities to restore normal patterns of brain activity, and thereby treat the illness."

As mentioned in our previous post on deep brain stimulation (‪‎DBS‬), this form of neurostimulation which is being studied at Toronto's University Health Network, is also being offered as an experimental treatment to patients with ‪‎anorexia‬ and mild forms of ‪Alzheimer‬'s and it's already showing promise for both.

For patients with moderate-severe depression that is refractory to traditional pharmacologics and psychotherapy, many struggle with what to offer next for treatment. However, recently there has been a growing trend towards investigating and using neurostimulation modalities, such as ‪ECT‬ and ‪DBS‬ (deep brain stimulation).

While first used for treatment of Parkinson's, neuropsychiatrists and researchers at the University of Toronto and the Toronto Western Hospital are now studying the use and efficacy of DBS for patients with refractory ‪‎depression‬, ‪anorexia‬ nervosa, and ‪Alzheimer‬'s.